I remember Dr. Redhawk had some comments on what he does so I tracked several down.
"I chop and drop, rape, 7 top turnip, daikon, winter peas, even grains work well, just chop before seed out.
The best plant for preventing erosion is Lucerne (alfalfa) the roots are massive in number and deep in the soil (over 4 feet deep is normal), clovers are great for this too.
I use a blend of something around 20 different plant species for covers, four of them are clovers, buckwheat, alfalfa, cereal rye, fescue, annual rye, rape, seven top turnip and on and on.
The reason for this is to get variety and thus diversity along with the many different root growth patterns, bacteria diversity, fungal diversity, the more different plants that are used, the better the end result soil will be."